C++ 类的存储空间及数据成员变量覆盖

class Empty {
};

class EmptyNonVirtual {
public:
EmptyNonVirtual() {}
~EmptyNonVirtual() {}
};

class EmptyVirtual {
public:
EmptyVirtual() {}
virtual~EmptyVirtual() {}
};

class Base1 {
public:
Base1() {}
void print() {}
};

class Base2 {
public:
short m;
Base2() { m = 3; std::cout << "construct Base2.m=" << this->m << std::endl; }
void print() {   std::cout << "print           m=" << this->m << std::endl; }
};

class F1 : public Base2 {
public:
short m;
F1() { m = 4; std::cout << "construct    F1.m=" << this->m << std::endl; }
};

class F2A: public F1  {
public:
char* c;
};

class F2B : public F1  {
private:
char str;
};

int test() {
//
std::cout << "Empty           size = " << sizeof (Empty) << std::endl;
std::cout << "EmptyNonVirtual size = " << sizeof (EmptyNonVirtual) << std::endl;
std::cout << "EmptyVirtual    size = " << sizeof (EmptyVirtual) << std::endl;
//
std::cout << "Base1 size = " << sizeof (Base1) << std::endl;
std::cout << "Base2 size = " << sizeof (Base2) << std::endl;
std::cout << "F1    size = " << sizeof (F1) << std::endl;
std::cout << "F2A   size = " << sizeof (F2A) << std::endl;
std::cout << "F2B   size = " << sizeof (F2B) << std::endl;
//
F1 f1;
f1.print();
std::cout << "f1.m=" << f1.m << std::endl;
//
return 0;
}

d:\mylaf\project\vs2013\project_code\testvirtualinputv2\mainvirtualinputv2.cc
Empty           size = 1
EmptyNonVirtual size = 1
EmptyVirtual    size = 4
Base1 size = 1
Base2 size = 2
F1    size = 4
F2A   size = 8
F2B   size = 6
construct Base2.m=3
construct    F1.m=4
print           m=3
f1.m=4